New 20 MPH speed limit to also apply to bikes in Southwark

The Parks byelaws is also incorrect - local traffic authorities have no powers to set speed limits for bicycles. Although they regularly do (cf. Richmond Park).

It's not a byelaw. It's "The Royal Parks and Other Open Spaces Regulations 1997" act:-

http://www.legislation.gov.uk/uksi/1997/1639/contents/made

(Note that's the original act, there are a whole bunch of amendments to it...)